Historical clue formulations

• People for whom two states are named — 2023-07-12
• Territory name until 1889 — 2018-09-02
• ___ Territory — 2018-06-29
• 19th-century Midwest territory — 2017-12-20
• Indian tribe that lent its name to two states — 2017-01-23
• Word seen twice on a U.S. map — 2015-10-14
• Territory divided into two states — 2013-04-23
• Territory that became two states — 2013-01-21
• Some Plains Indians — 2007-07-11
• End of two state names — 2006-07-24
• 1945 John Wayne western — 2004-08-04
• Sitting Bull, e.g. — 2000-12-22
• Sitting Bull, e.g. — 1998-08-06
• Noted Big Apple residence, with "the" — 1998-03-03
• Sioux Indian — 1994-10-10
• Lennon's last home, with "The" — 1994-01-27